ID 679 - Chitozan

PL: Chitozan
EN: Chitosan
Pdf: chitosan

1. Charakterystyka żywności / składnika

The food constituent that is the subject of the health claim is chitosan.
Chitosan is a linear cationic polysaccharide composed of randomly distributed -(1-4)-linked D-glucosamine and N-acetyl-D-glucosamine produced commercially by the deacetylation of chitin, which is a component of the exoskeleton of crustaceans and the cell walls of fungi. The degree of deacetylation can be measured by established methods, and ranges from 60-100 % in commercial preparations. The molecular weight of chitosan in commercial preparations ranges from 3,800 to 20,000 Da. Chitosan is insoluble in water.
The Panel considers that the food constituent, chitosan, which is the subject of the health claims, is sufficiently characterised.

2.1. Redukcja masy ciała (ID 679, 1499)

The claimed effect is “weight management”. The Panel assumes that the target population is overweight individuals in the general population who wish to reduce their body weight.
In the context of the proposed wordings and references provided, the Panel assumes that the claimed effect relates to a reduction in body weight.
Weight loss can be interpreted as the achievement of a normal body weight in previously overweight subjects. In this context, weight loss in overweight subjects without the achievement of a normal body weight is considered to be a beneficial physiological effect.
The Panel considers that a reduction in body weight is a beneficial physiological effect.

3.1. Redukcja masy ciała (ID 679 and 1499)

The references provided for the scientific substantiation of the claim included narrative reviews and book chapters which did not provide original data for a scientific evaluation, one human intervention study which investigated the effects of a combination of chitosan and glucomannan on body weight, and one intervention study using chitosan which did not report on body weight. Two references on internal reports were not available to the Panel even after every reasonable effort had been made to
retrieve them. The Panel considers that no conclusions can be drawn from these references for the scientific substantiation of the claim.
In addition, one meta-analysis of randomised controlled trials (RCTs, Ernst and Pittler, 2000), one Cochrane systematic review and meta-analysis of RCTs (Ni Mhurchu et al., 2005) and seven human intervention studies on the effect of chitosan on body weight were provided. The Panel notes that all of the intervention studies provided, and those included in the systematic review and meta-analysis, were considered in a more recent update of the Cochrane systematic review (Jull et al., 2008), which was considered by the Panel for the scientific evaluation of the claim. This systematic review was restricted to RCTs which assessed the effects of chitosan on body weight, compared to placebo or standard care in adult overweight or obese males and females, and which had a minimum duration of four weeks. A total of 15 studies out of 42 identified met the inclusion criteria, and these studies comprised a total of 1,216 participants (640 allocated to chitosan and 640 to placebo) with a mean age of 44 years (range 18 to 70 years). Mean trial duration was 8.3 weeks (range 4-24 weeks) and mean study size was 81 subjects (range 24 to 250). All trials compared chitosan at doses ranking from 0.24 g/day to 15 g/day (mean 3.7 g/day) to placebo, but five studies did not report any dose (Colombo and Sciutto, 1996; Giustina and Ventura, 1995; Sciutto and Colombo, 1995; Veneroni et al., 1996; Woodgate and Conquer, 2003). Sufficient data on body weight were available only for 13 trials, which were considered for data analysis (Colombo and Sciutto, 1996; Giustina and Ventura, 1995; Ho et al., 2001; Kaats et al., 2006; Macchi, 1996; Ni Mhurchu et al., 2004; Pittler et al., 1999; Schiller et al., 2001; Sciutto and Colombo, 1995; Veneroni et al., 1996; Williams, 1998; Woodgate and Conquer, 2003; Zahorska-Markiewicz et al., 2002). Seven studies (Colombo and Sciutto, 1996; Girola et al., 1996; Giustina and Ventura, 1995; Kaats et al., 2006; Sciutto and Colombo, 1995; Veneroni et al., 1996; Woodgate and Conquer, 2003) used treatment preparations which contained other active ingredients in addition to chitosan, while the remainder used chitosan alone. The treatment preparations contained, in addition to chitosan, guar gum, ascorbic acid and other micronutrients (Colombo and Sciutto, 1996; Giustina and Ventura, 1995; Sciutto and Colombo, 1995; Veneroni et al., 1996), glucomannan, fenugreek, Gymnema sylvestre and vitamin C (Woodgate and Conquer, 2003), Garcinia cambogia extract and chrome (Girola et al., 1996), and beta-glucan, snow white oat fibre, betamine HCL and aloe saponins (Kaats et al., 2006). The Panel considers that no conclusions can be drawn from these studies, and thus from the meta-analysis in which they were included, for the scientific substantiation of the claim.
When the analysis was limited to trials which used chitosan alone as intervention (Ho et al., 2001; Macchi, 1996; Ni Mhurchu et al., 2004; Pittler et al., 1999; Schiller et al., 2001; Wuolijoki et al., 1999; Zahorska-Markiewicz et al., 2002), a small but statistically significant weight loss of -0.9 kg (95 % CI -1.4 to -0.4, p=0.0009) was observed with chitosan compared to placebo. However, when the analysis was limited to trials that met the allocation concealment quality criteria (Ni Mhurchu et al., 2004; Pittler et al., 1999; Schiller et al., 2001), no significant differences between the effect of chitosan and placebo on body weight changes were observed (-0.6 kg, 95 % CI -1.3 to 0.1, p=0.09). Similar results were obtained when the analysis was limited to studies of six months duration (Ni Mhurchu et al., 2004; Zahorska-Markiewicz et al., 2002). The Panel notes that this meta-analysis does not show an effect of chitosan consumption on body weight loss.
The mechanism by which chitosan is presumed to exert the claimed effect is by binding to negatively charged lipids and hence reducing their gastro-intestinal uptake, and these effects were observed in some animal studies (Deuchi et al., 1995; Sugano et al., 1980; Zacour et al., 1992). However, the effects of chitosan on 24 h faecal fat excretion in healthy human volunteers at doses of about 3 g daily were not statistically significant, and thus were unlikely to have an impact on body weight (Guerciolini et al., 2001).
In weighing the evidence, the Panel took into account that a meta-analysis of RCTs, which included all the individual human intervention studies submitted for the scientific substantiation of the claim
and which investigated the effects of chitosan consumption on body weight, did not show a significant effect of chitosan when only studies that met the allocation concealment quality criteria were considered for analysis.
The Panel concludes that a cause and effect relationship has not been established between the consumption of chitosan and reduction in body weight.

Warunki i możliwe ograniczenia stosowania oświadczenia

6x250mg/jour